By (+ a time) ='not later than':
* I posted the letter today, so they should receive it by Monday. (= on or before Monday, not later than Monday)
* We'd better hurry. We have to be at home by 5 o'clock. (=at or before 5 o'clock, not later than 5 o'clock)
* Where's Sue? She should be here by now. (=now or before now - so she should have arrived already)
You cannot use until with this meaning:
* Tell me by Friday whether or not you can come to the party. (not 'Tell me until Friday')
We use until (or till) to say bow long a situation continues:
* 'Shall we go now?' 'No, let's wait until (or till) it stops raining.'
* I couldn't get up this morning. I stayed in bed until half past ten.
* I couldn't get up this morning. I didn't get up until half past ten.
Compare until and by:
1 until
Something continues until a time in the future:
* Fred will be away until Monday. (so he'll be back on Monday)
* I'll be working until 11. 30. (so I'll stop working at 11.30)
2 by
Something happens by a time in the future:
* Fred will be back by Monday. (= he'll be back not later than Monday)
* I'll have finished my work by 11. 30. (I'll finish my work not later than 11. 30)
You can say 'by the time something happens'. Study these examples:
* It's not worth going shopping now. By the time we get to the shops, they will be closed. (= the shops will close between now and the time we get there)
* (from a letter) I'm flying to the United States this evening. So by the time you receive this letter, I'll be in New York. (= I will arrive in New York between now and the time you receive this letter)
* Hurry up! By the time we get to the cinema, the film will already have started.
You can say 'by the time something happened"(for the past):
* Jane's car broke down on the way to the party last night. By the time she arrived, most of the other guests had gone. (= it took her a long time to get to the party and most of the guests went home during this time)
* I had a lot of work to do yesterday evening. I was very tired by the time I finished. (= it took me a long time to do the work and I became more and more tired during this time)
* We went to the cinema last night. It took us a long time to find somewhere to park the car. By the time we got to the cinema, the film had already started.
Also by then or by that time:
* Jane finally arrived at the party at midnight, but by then (or by that time), most of the guests had gone.
EXERCISES
119.1 Make sentences with by.
1. I have to be at home not later than 5 o'clock. _I have to be at home by 5 o'clock._
2. I have to be at the airport not later than 10.30. 1 have to be at the airport ---.
3. Let me know not later than Saturday whether you can come to the party. Let me know ---.
4. Please make sure that you're here not later than 2 o'clock. Please ---.
5. If we leave now, we should arrive not later than lunchtime.
119.2 Put in by or until.
1. Fred has gone away. He'll be away _until_ Monday.
2. Sorry, but I must go. I have to be at home _by_ 5 o'clock.
3. I've been offered a job. I haven't decided yet whether to accept it or not. I have to decide --- Thursday.
4. I think I'll wait --- Thursday before making a decision.
5. It's too late to go shopping. The shops are only open --- 5. 30. They'll be closed now.
6. I'd better pay the phone bill. It has to be paid --- tomorrow.
7. Don't pay the bill today. Wait --- tomorrow.
8. A: Have you finished redecorating your house?
B: Not yet. We hope to finish --- the end of the week.
9. A: I'm going out now. I'll be back at 4.30. Will you still be here?
B: I don't think so. I'll probably have gone out --- then.
10. I'm moving into my new flat next week. I'm staying with a friend --- then.
11. I've got a lot of work to do. --- the time I finish, it will be time to go to bed.
12. If you want to do the exam, you should enter --- 3 April.
119.3 Use your own ideas to complete these sentences. Use by or until.
1. Fred is away at the moment. He'll be away _until Monday._
2. Fred is away at the moment. He'll be back _by Monday._
3. I'm just going out. I won't be very long. Wait here ---.
4. I'm going shopping. It's 4.30 now. I won't be very long. I'll be back ---.
5. If you want to apply for the job, your application must be received ---.
6. Last night I watched TV ---.
119.4 Read the situations and complete the sentences using By the time ...
1 Jane was invited to a party but she got there much later than she intended.
_By the time she got to the party_, most of the other guests had gone.
2. I had to catch a train but it took me longer than expected to get to the station.
---, my train had already gone.
3. I saw two men who looked as if they were trying to steal a car. I called the police but it was some time before they arrived. ---, the two men had disappeared.
4. A man escaped from prison last night. It was a long time before the guards discovered what had happened. ---, the escaped prisoner was miles away.
5. I intended to go shopping after finishing my work. But I finished my work much later than expected. ---, it was too late to go shopping.
119.1
2 by 10.30
3 by Saturday whether you can come to the party.
4 Please make sure you're here by 2 o'clock. or Please be here ...
5 If we leave now, we should arrive by lunchtime.
119.2
3 by 4 until
5 until ... by
6 by 7 until
8 by 9 by
10 until 11 By
12 by
119.3 Example answers:
3 until I comeback.
4 by 5 o'clock.
5 by next Friday.
6 until midnight.
119.4
2 By the time I got to the station
3 By the time the police arrived
4 By the time the guards discovered what had happened
5 By the time I (had) finished my work
